Control Of Wet Strength Resin Fouling Of Paper-Making Felt

ABSTRACT

Methods and systems for making paper and controlling wet strength resin fouling of paper-making felt are provided. Wet strength resin fouling, including degradation, clogging, changes in absorption, or a combination thereof, can be controlled by applying a formulation that contains an organic acid, to the felt, before a paper-making pulp containing wet strength resin is applied to the felt. The formulation can include, for example, an alpha-hydroxy acid such as glycolic acid. In addition to the at least one organic acid, the formulation can include various surfactants, polymers, amines, emulsifiers, wetting agents, and/or other additives.

This application claims the benefit under 35 U.S.C. §119(e) of prior U.S. Provisional Patent Application No. 61/562,456, filed Nov. 22, 2011, which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to methods and systems for controlling wet strength resin fouling of paper-making felts. The paper-making industry lacks an effective method and system to efficiently control wet strength resin fouling of felt. Strong oxidant-based formulations, such as chlorine-based products, have been used but can make felt very weak and also present safety and environmental concerns. Wet strength resin fouling of felts can cause a papermaking mill to spend much time and money changing felts frequently. Current felt conditioner products only exhibit a small effect on preventing wet strength resin deposition on a paper-making machine felt. A paper-making process can require a replacement felt every several weeks due to such fouling, at significant cost. An increase of just one day in felt life will result in significant savings.

Current fouling control products are mainly solvent-based or oil-based. Such products may cause volatile organic compound (VOC) problems or concerns, can cause odor issues, and/or may make the felt hydrophobic, negatively impacting water absorption and water transfer. Accordingly, a need exists for preventing or minimizing wet strength resin fouling of paper-making felts, and for reducing fouling that has already occurred on a felt.

SUMMARY OF THE PRESENT INVENTION

It is therefore a feature of the present invention to provide methods for reducing wet strength resin fouling of a paper-making felt.

Another feature of the present invention is to minimize cross-linking of a wet strength resin to a paper-making felt and to dislodge wet strength resin that is deposited on a felt.

A further feature of the present invention is to extend the life span of a paper-making felt and improve felt drainage.

Yet another feature of the present invention is to provide a washing and conditioning product for a continuous felt, which keeps the felt clean and maintains good water absorption and good water transferability.

Additional features and advantages of the present invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the description below and appended claims.

To achieve these and other advantages, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention relates to a method of making paper, which includes treating a paper-making felt with a treatment formulation. The paper-making felt can be susceptible to wet strength resin fouling that occurs when the felt is contacted with a wet strength resin(s). The treatment formulation can include at least one organic acid. The method can further include applying paper-making pulp to the paper-making felt after treating the felt, wherein the paper-making pulp includes a wet strength resin. The method can further include making a paper from the paper-making pulp applied to the paper-making felt, wherein the organic acid is applied in an amount effective to control wet strength resin fouling that would otherwise be attributable to the paper-making pulp.

The present invention also relates to a method of controlling wet strength resin fouling on a paper-making felt. The method can include treating a paper-making felt that is susceptible to wet strength resin fouling, with a formulation that includes at least one organic acid. The method can further include making paper on the paper-making felt using a paper-making pulp that includes a wet strength resin. In accordance with the method, at least one organic acid can be applied to the paper-making felt in an amount effective to control wet strength resin fouling that would otherwise occur due to the wet strength resin content in the paper-making pulp.

The present invention further relates to a system of making paper, which can include the following components. A paper-making felt that is susceptible to wet strength resin fouling when contacted with a wet strength resin can be included. At least one applicator configured to treat the paper-making felt with a formulation including at least one organic acid can be included. A source of the formulation in fluid communication with the first applicator can be included. A paper-making former to apply a paper-making pulp, including the wet strength resin, to the paper-making felt can be included. A source of the paper-making pulp in fluid communication with the paper-making former can be included. In accordance with the system, the applicator(s) can be configured to apply an amount of the formulation effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp. More than one applicator can be used and be optionally located upstream or downstream of the first applicator.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a further explanation of the present invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic, side view of an exemplary paper-making system of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

A method of making paper according to the present invention includes treating a paper-making felt that is susceptible to wet strength resin fouling, with an anti-fouling formulation. The formulation includes at least one organic acid. The method can further include applying a paper-making pulp to the paper-making felt after the felt is treated with the anti-fouling formulation. The paper-making pulp can contain a wet strength resin that would otherwise foul the felt, but for the treatment. The method can further include making paper from the paper-making pulp after the pulp is applied to the paper-making felt. The at least one organic acid can be applied to the paper-making felt in an amount effective to control wet strength resin fouling that would otherwise be caused by the wet strength resin in the paper-making pulp.

The present invention also includes a method to control wet strength resin fouling on a paper-making felt. The method can include treating a paper-making felt that is susceptible to wet strength resin fouling, with a formulation that includes at least one organic acid. The method can further include making a paper on the paper-making felt, after application of the formulation, by using a paper-making pulp that includes a wet strength resin. In accordance with the method, the at least one organic acid can be applied to the paper-making felt in an amount effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp.

The present invention also provides a system for making paper by using a paper-making felt. A paper-making felt can be used that is susceptible to wet strength resin fouling. The present invention, however, controls such fouling. One or more applicators can be configured to treat the paper-making felt with a formulation including at least one organic acid. A source of the formulation can be in fluid communication with the applicator(s). The applicator(s) can include a spray nozzle, a jet sprayer, a faucet, a dipping tank, a trough, or the like. A paper-making former can apply a paper-making pulp that includes a wet strength resin, to the paper-making felt after the felt is treated with the formulation. A source of the paper-making pulp can be in fluid communication with the paper-making former. In accordance with the system, the applicator(s) can be configured to apply an amount of the formulation that is effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp. The amount applied can be empirically calculated, stoichiometrically calculated, calculated based on the wet strength resin concentration in the paper-making pulp, calculated based on the amount of paper-making pulp to be applied to the felt, or calculated based on a combination thereof. Independent of calculations, the felt can be treated, contacted with, or thoroughly soaked on one or more surfaces, in a formulation containing about 95 wt % or less water, for example, about 75 wt. % or less water, 60 wt. % or less water, 50 wt. % or less water, or from about 40 wt. % to about 60 wt. % water, based on the total weight of the formulation.

As illustrated in FIG. 1, a system can be provided wherein a continuous paper-making felt 86 is looped around and continuously run by end rollers 67 and 72. A paper making former, 66, which can include a fourdrinier, twin wire former, Gap former, cylinder former, or any other type of paper making former can be in fluid communication with a supply or source of a paper-making pulp and can be configured to continuously apply the pulp to felt 86, for example, while felt 86 is moved in the direction shown by the arrow 87. The applicator 74 can be positioned to apply, as by spraying or otherwise applying, a treatment formulation according to the present invention, formulated to control wet strength resin fouling of felt 86. The treated felt can move in the direction shown by arrow 87 and over a support roller 68 and through the press formed by rolls 69 and 70. The press can include a tri-nip press, through press, shoe press, or any other papermaking press, or no press at all. An optional second treatment of felt 86 can be fed into applicator 79 arranged on the outside side of the felt after the uhle box 82, also called a vacuum box, suction box, or flat box. This second treatment can be with the same or different treatment formulation of the present invention. Rolls 67 and 68 can include a porous surface or otherwise include holes or apertures through which excess pulp and/or water can drain through and recovered, for example, to be re-circulated or sent to a waste receptacle. After passing out of rolls 67 and 68, the pulp-coated felt can then pass over a roll 72 and be transferred to the drying section. The drying section 73 can be a Yankee dryer, Through Air Dryer, cylinder dryers, Flakt dryer or any other papermaking dryer section. As the resulting paper product is taken up into the dryer section, continuous paper-making felt 86 is moved by end roller 72 back toward end roller 67 so that the process can be continued. As paper-making felt 86 moves back toward end roller 67, it can pass by high pressure shower 80 which can be used to clean the felt. High pressure shower 80 typically oscillates to provide uniform coverage to the paper-making felt 86. Paper-making felt 86 then passes by lube shower 81 and over a vacuum box or a Uhle box 82 which is used to clean and dry felt 86 before felt 86 is looped back for use in a next cycle. FIG. 1 illustrates a press section containing one felt. The press section can contain more than one felt.

The continuous paper-making felt can be treated and used in a system such as that illustrated in FIG. 1. The entire system shown in FIG. 1 can be incorporated and housed inside a chamber. Alternatively, at least the end rollers can be located outside of a chamber while first and second applicators 74 and 79, respectively, can be located within the chamber.

The paper-making felt used in the method and system can be composed of any suitable material or combination of materials. The material used can include artificial material, natural material, or a combination thereof. The felt can be polymeric, such as thermoplastic or thermoset. Examples of suitable felt materials include polyester(s), nylon, polyethylene, polypropylene, other polyalkylenes, blends thereof, or combinations thereof. The paper-making felt can include a grid. For example, the felt can include a grid made of a polymer containing, as a recurring amide group, CONH.

The paper-making felt can have any desired geometry and can be mounted in any suitable manner. The felt can be in one or more sections on one or more sets of rollers. The paper-making felt can include or be mounted on or as a continuous belt although non-continuous belts and lengths of felt can also be useful. The paper-making felt can include a rotating continuous conveyor belt, for example, a loop mounted around two end rollers. The treatment formulation can be applied at least once per revolution of the rotating conveyor belt. For example, the formulation can be applied at a first station and, optionally, at one or more additional stations. The formulation can be applied continuously, semi-continuously, or periodically to the paper-making felt during each revolution of the felt or other shorter or longer interval. The method can further include applying additional amounts of the formulation to the paper-making felt after making and/or removing a paper product. The treatment formulation can be applied using any suitable process. The formulation can be dripped, brushed, and/or sprayed onto the paper-making felt. The paper-making felt can be soaked or immersed in the formulation, or in a solution containing the formulation, or pulled through the formulation, for example, through a trough containing the formulation. The formulation can include a solution of the at least one organic acid.

The pH of the solution can be less than or equal to about 1.0, 2.0, 3.0, 4.0, or 7.0. The pH of the formulation can be from about 1 to about 3, or from about 1.5 to about 2.8, or from about 2 to 2.5 and the like.

Any type of paper can be made using the methods of the present invention. For example, cardboard, paperboard, paper, toilet paper, tissue paper, paper towels, corrugated board, and linear board can be made using the system and methods of the present invention. The formulation can be applied to control any kind of wet strength resin fouling that can foul and/or damage the paper-making felt. For example, the wet strength resin fouling can include degradation of the felt, clogging of the felt, and/or decreased drainage, or any combinations thereof. The control of wet strength resin fouling attained by the present invention can include prevention, reduction, minimization, remediation, or any combinations thereof, of felt clogging, felt degradation, and/or drainage loss.

The methods of the present invention can use any type, amount, or combination of wet strength resins. Examples of wet strength resins that cause fouling that can be controlled by the present invention include diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), formaldehyde-based resin, glyoxal-polyacrylamide, urea-formaldehyde (UF), melamine-formaldehyde (MF), polyamide-epichlorohydrin (PEA), alkyl ketene dimer (AKD), alkyl succinic anhydride (ASA), epichlorhydrin resin(s), poly(amideamine)epichlorohydrin (PAE), or any combinations thereof, or any resins to be considered in these family of resins.

The organic acid can include any type, amount, or combination of organic acids. The organic acid can include at least one alpha-hydroxy acid. Examples of alpha-hydroxy acids include glycolic acid, lactic acid, citric acid, mandelic acid, or any combinations thereof. The organic acid can be present in a stoichiometric amount sufficient to react with or otherwise interact or treat a portion or substantially all of the wet strength resin that would otherwise react or degrade with the paper-making felt. The organic acid can be or include glycolic acid, and, as an example, the wet strength resin can be or includes poly(amideamine)epichlorohydrin (PAE), wherein the glycolic acid is applied in an amount, for instance, that is stiochiometrically sufficient to react or otherwise treat a portion or substantially all of the wet strength resin that would otherwise react with the paper-making felt. For instance, the formulation need not be applied to an extent that all of the wet strength resin is prevented from reacting, but rather in an amount that substantially prevents the wet strength resin from reacting with or adhering to the felt (e.g., preventing, for instance, at least 70%, at least 80%, at least 90%, at least 95%, at least 99% by weight from reacting). The application to the felt prior to application of the pulp can enable much of the wet strength resin to react with other pulp ingredients, without being neutralized, but still controls reactivity between the wet strength resin and the felt itself.

In addition to the at least one organic acid, the formulation can further include one or more other components. One or more of these components can increase the effectiveness of the organic acid, and/or permit better application of the organic acid, and/or better distribution of the organic acid on the web, and/or buffers and/or pH adjusters and/or other advantages. As an example, at least one surfactant (e.g., at least one non-ionic surfactant and/or at least one ionic surfactant), and/or at least one washing surfactant, and/or at least one wetting agent, and/or at least one emulsifier, and/or at least one amine and/or water can be present in the formulation along with the organic acid. If more than one category of component is present in the formulation in addition to the organic acid, the additional two or more components are different from each other. Several types of surfactants can be used at one time. For instance, at least one cationic surfactant and at least one non-ionic surfactant can be present.

The formulation can include from 0 wt % to 25 wt %, from about 0.2 wt % to about 20 wt %, from about 2.0 wt. % to about 15 wt. %, from about 6.0 wt. % to about 8.0 wt. %, or about 7.0 wt. %, of at least surfactant(s).

The formulation can include from about 0 wt % to about 8 wt %, from about 0.15 wt % to about 7.5 wt %, from about 1.5 wt. % to about 7.5 wt. %, from about 4.0 wt. % to about 6.0 wt. %, or about 5.0 wt. %, of at least one cationic surfactant.

The formulation can include from about 0 wt % to about 8 wt %, from about 0.15 wt % to about 7.5 wt %, from about 1.5 wt. % to about 7.5 wt. %, from about 4.0 wt. % to about 6.0 wt. %, or about 5.0 wt. %, of at least one anionic surfactant.

The formulation can include from about 0 wt % to about 40 wt %, from about 1.5 wt % to about 35 wt %, from about 15 wt. % to about 35 wt. %, from about 20 wt. % to about 30 wt. %, or about 25 wt. %, of the at least one organic acid.

The formulation can include from about 0 wt % to about 15 wt %, from about 0.1 wt % to about 10 wt %, from about 1.0 wt. % to about 10 wt. %, from about 4.0 wt. % to about 6.0 wt. %, or about 5.0 wt. %, of at least one washing surfactant.

The formulation can include from about 0 wt % to about 8 wt %, from about 0.15 wt % to about 7.5 wt %, from about 1.5 wt. % to about 7.5 wt. %, from about 4.0 wt. % to about 6.0 wt. %, or about 5.0 wt. %, of at least one emulsifier.

The formulation can include from about 0 wt % to about 10 wt %, and/or from about 0.05 wt % to about 5.5 wt %, from about 0.5 wt. % to about 5.5 wt. %, from about 2.0 wt. % to about 4.0 wt. %, or about 3.0 wt. %, of at least one wetting agent.

The formulation can include from about 0 wt % to about 10 wt %, from about 0.1 wt % to about 8 wt %, from about 0.3 wt % to about 5 wt %, from about 0.5 wt % to about 5 wt %, from about 1 wt % to about 3 wt % of at least one amine. The amine can be an ethanol amine(s). Amines can include ammonia, ammonium hydroxide, dimethylamine, monomethyl amine, mono ethanol amine, diethanol amine, triethanol amine, or any combinations thereof.

The balance of any formulation can contain water and/or other aqueous solutions. Water can be present in the formulation, for instance, to control spray characteristics, concentrations, and/or viscosity and the like.

In the present invention, all weight percentages (wt. %) are based on the total weight of the formulation, unless stated otherwise.

As an option, in addition to the at least one organic acid, the formulation can further include at least one propylene oxide ethylene oxide block copolymer surfactant, and/or at least one secondary alcohol ethoxylate non-ionic surfactant, and/or at least one alcohol ethylene oxide non-ionic surfactant, n-alkyl dimethyl benzyl ammonium chloride (e.g., n=12-18, or more than one), and/or water. The formulation can include water. The formulation can include, e.g. from about 0.2 wt % to about 12 wt %, from about 2.0 wt. % to about 12 wt. %, from about 6.0 wt. % to about 8.0 wt. %, or about 7.0 wt. % of at least one propylene oxide ethylene oxide block copolymer surfactant. The formulation can include, e.g., from about 0.15 wt % to about 7.5 wt %, from about 1.5 wt. % to about 7.5 wt. %, from about 4.0 wt. % to about 6.0 wt. %, or about 5.0 wt. % of at least one alkyl dimethyl benzyl ammonium chloride. The formulation can include, e.g., from about 1.5 wt % to about 35 wt %, from about 15 wt. % to about 35 wt. %, from about 20 wt. % to about 30 wt. %, or about 25% of glycolic acid. The formulation can include, e.g., from about 0.1 wt % to about 10 wt %, from about 1.0 wt. % to about 10 wt. %, from 4.0 wt. % to about 6.0 wt. %, or about 5.0 wt. % of at least one secondary alcohol ethoxylate non-ionic surfactant. The formulation can include e.g., from about 0.05 wt % to about 5.5 wt %, from about 0.5 wt. % to about 5.5 wt. %, from about 2.0 wt. % to about 4.0 wt. %, or about 3.0 wt. %, of at least one alcohol ethylene oxide non-ionic surfactant. All weight percentages being based on the total weight of the formulation.

The formulation can include the organic acid and/or one or more chemicals to deactivate a wet strength resin functional group to prevent or minimize cross-linking to a paper-making felt. An organic acid can be used to drop the pH of the paper-making pulp to help prevent cross-linking of the wet strength resin. A high molecular weight surfactant can be used to form a physical barrier on the paper-making felt to prevent direct contact with wet strength resin from the pulp. A wetting agent, washing agent, and/or emulsifier can be used to swell, loosen, and remove deposits of wet strength resin from the surface of a paper-making felt. A cationic surfactant can be used to prevent anionic materials, for example, a wet strength resin, from depositing onto the surface of the paper-making felt.

An amine or alcohol amine can be present to optionally react with the organic acid, such as the glycolic acid to form a secondary amide which can further optionally deactiviate or partially deactivate the wet strength resin. The amine or alcohol amine can optionally adjust the pH of the formulation, such as to a pH of 2 or higher. The amine or alcohol amine can optionally reduce or prevent possible corrosion by the organic acid.

An example of a formulation that can be used in the methods and systems of the present invention is listed in TABLE 1 and TABLE 2. The TABLE 1 formulation was tested in the EXAMPLES below and is listed as Formulation 1 in TABLES 3-5 below. In the EXAMPLES below, the formulation was diluted with water to form a 10 wt % in aqueous solution.

TABLE 1 PRODUCT FORMULATION Chemical Content (by weight) PLURONIC ® F-108 7% MAQUAT LC 12S-50% 10% Glycolic Acid (70% solution) 25% TERGITOL 15-S-20 5% TOMADOL ® 1-5 3% Water 50% Total 100%

TABLE 2 PRODUCT FORMULATION Chemical Content (by weight) TOXIMUL 8320  5% MAQUAT LC 12S-50% 15% Glycolic Acid (70% solution) 27% PLURONIC L-62 0 to 3% TOMADOL ® 1-5  5% Monoethanolamine 2% to 3% Water 46% Total 100% 

Glycolic acid and/or any organic acid used herein can be supplied in any form as either a free acid or a salt. The organic acid, e.g., glycolic acid, can react with a wet strength resin functional group to deprive its ability (or reduce its ability) to cross-link and react with a paper-making felt, for example, one made from a polymer, such as nylon. Glycolic acid advantageously is generally odorless and very low in volatile organic compounds (VOC) compared to other short chain organic acids. The extra hydroxyl group in glycolic acid (or other alpha-hydroxy acid) causes reacted wet strength resin to be more water dispersible. Glycolic acid is a safe organic acid that is used in the cosmetic industry. Glycolic acid can help maintain a pH lower than 5, which can significantly prevent a wet strength resin from cross-linking with paper-making felt.

The high molecular weight polymer-like propylene oxide/ethylene oxide block polymer surfactant, e.g., PLURONIC® F-108, available from BASF Corporation of Florham Park, New Jersey, can be used as part of the present formulations. This surfactant can “coat” the surface of paper-making felt and form a physical barrier to prevent the wet strength resin from directly contacting the felt. The surfactant can keep the paper-making felt hydrophilic to make water absorption and transfer more efficient.

The washing surfactant, e.g., TERGITOL 15-S-20, available from The Dow Chemical Company of Midland, Michigan, can be used as part of the present formulations. The washing surfactant can cause deposits, not only from wet strength resin deposits, but also other contaminants from recycling pulp, to be washed out of a felt efficiently. The wetting agent, e.g., TOMADOL® 1-5, available from Air Products and Chemicals, Inc. of Allentown, Pa., can cause hydrophobic deposits on felt to be more water dispersible.

The cationic surfactant, such as a quaternary amine-based cationic surfactant, e.g., MAQUAT LC 12S-50%, available from Mason Chemical Company of Arlington Heights, Ill., can make the felt at least partially cationic to help prevent deposition of wet strength resin. The cationic surfactant can also slow down wet strength resin reaction speed and potential for cross-linking. The washing surfactant can be a solid at room temperature and can be pre-heated to melt and then pumped or sucked into a vessel.

An emulsifier(s) can be present in the formulation. One example is TOXIMUL 8320 from Stephan. An emulsifier can aid in handling any cross-linked wet strength resin and/or other hydrophobic contaminants present and/or prevent or reduce the amount that deposits on the felt.

A wetting agent(s) can be present in the formulation. One example is PLURONIC L-62. A wetting agent(s) can help in washing and/or preventing hydrophobic contaminants from depositing on the felt.

The treatment formulation of the present invention can be prepared in any manner. For instance, each of the components of the formulation can be added together into a mixer or vessel in order to be combined as a formulation. The mixing of the various components to form the treatment formulation of the present invention can be done at room temperature or elevated temperature. The time for mixing the various components together can be any time period, for instance, from 1 minute to 100 minutes or more. The various components of the treatment formulation can be added together at the same time, or in sequence, or in any combination to form the treatment formulation of the present invention. As an option, and for purposes of the present invention, the treatment formulation further includes the individual application of one or more components that form the treatment formulation onto the felt as separate formulations. For instance, at least one organic acid can be separately applied to the felt, and, in another application or multiple applications, at the same time or different time, other components of the treatment formulation can be applied, such as the optional surfactant(s) (e.g., cationic surfactant and/or non-ionic surfactant), emulsifier(s), wetting agent(s), amine(s) (e.g., alcohol amines), and the like.

The present invention includes the following aspects/embodiments/features in any order and/or in any combination:

-   1. The present invention relates to a method of making paper,     comprising:

treating a paper-making felt with a formulation, the paper-making felt being susceptible to wet strength resin fouling when contacted with a wet strength resin, the formulation comprising at least one organic acid;

applying paper-making pulp to the paper-making felt after the treating, the paper-making pulp comprising the wet strength resin; and making a paper from the paper-making pulp applied to the paper-making felt, wherein the at least one organic acid is applied to the paper-making felt in an amount effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp.

-   2. The method of any preceding or following     embodiment/feature/aspect, wherein the paper-making felt comprises a     continuous belt. -   3. The method of any preceding or following     embodiment/feature/aspect, wherein the wet strength resin fouling     comprises degradation, clogging, or both. -   4. The method of any preceding or following     embodiment/feature/aspect, wherein the wet strength resin comprises     an epichlorohydrin resin. -   5. The method of any preceding or following     embodiment/feature/aspect, wherein the wet strength resin comprises     poly(amideamine)epichlorohydrin (PAE). -   6. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid     comprises an alpha-hydroxy acid. -   7. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid     comprises glycolic acid. -   8. The method of any preceding or following     embodiment/feature/aspect, further comprising applying additional     amounts of the formulation to the paper-making felt after making the     paper. -   9. The method of any preceding or following     embodiment/feature/aspect, wherein the paper-making felt comprises a     rotating continuous conveyor belt and the formulation is applied at     least once per revolution of the rotating conveyor belt. -   10. The method of any preceding or following     embodiment/feature/aspect, wherein the treating comprises spraying     the formulation onto the paper-making felt. -   11. The method of any preceding or following     embodiment/feature/aspect, wherein the treating comprises soaking     the paper-making felt in a solution comprising the formulation. -   12. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation comprises a     solution of the at least one organic acid and the pH of the solution     is from about 1 to about 3. -   13. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation further comprises     at least one non-ionic surfactant, at least one washing surfactant,     at least one wetting agent, at least one cationic surfactant, and     water. -   14. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid     comprises glycolic acid and the formulation further comprises at     least one propylene oxide ethylene oxide block copolymer surfactant,     at least one secondary alcohol ethoxylate non-ionic surfactant, at     least one alcohol ethylene oxide non-ionic surfactant, alkyl     dimethyl benzyl ammonium chloride, and water. -   15. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation comprises from     about 2.0 wt. % to about 12 wt. % of at least one non-ionic     surfactant, from about 1.5 wt. % to about 7.5 wt. % of at least one     cationic surfactant, from about 15 wt. % to about 35 wt. % of at     least one organic acid, from about 1.0 wt. % to about 10 wt. % of at     least one washing surfactant, from about 0.5 wt. % to about 5.5 wt.     % of at least one wetting agent, based on the total weight of the     formulation, and water. -   16. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation comprises from     about 6.0 wt. % to about 8.0 wt. % of at least one propylene oxide     ethylene oxide block copolymer surfactant, from about 4.0 wt. % to     about 6.0 wt. % of at least one alkyl dimethyl benzyl ammonium     chloride, from about 20 wt. % to about 30 wt. % of glycolic acid,     from about 4.0 wt. % to about 6.0 wt. % of at least one secondary     alcohol ethoxylate non-ionic surfactant, from about 2.0 wt. % to     about 4.0 wt. % of at least one alcohol ethylene oxide non-ionic     surfactant, based on the total weight of the formulation, and water. -   17. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid is     present in a stoichiometric amount to react with substantially all     of the wet strength resin that would otherwise react with the     paper-making felt. -   18. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid     comprises glycolic acid, the wet strength resin comprises     poly(amideamine)epichlorohydrin (PAE), and the glycolic acid is     present in a stiochiometrically sufficient amount to react with     substantially all of the wet strength resin that would otherwise     react with the paper-making felt. -   19. The method of any preceding or following     embodiment/feature/aspect, wherein the paper-making felt comprises a     grid made of a polymer containing, as a recurring amide group, CONH. -   20. A method to control wet strength resin fouling on a paper-making     felt comprising:

treating a paper-making felt with a formulation, the paper-making felt being susceptible to wet strength resin fouling when contacted with a wet strength resin, the formulation comprising at least one organic acid; and

making a paper on the paper-making felt using a paper-making pulp comprising a wet strength resin;

wherein the at least one organic acid is applied to the paper-making felt in an amount effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp.

-   21. The method of any preceding or following     embodiment/feature/aspect, wherein the wet strength resin fouling     comprises degradation, clogging, or both. -   22. The method of any preceding or following     embodiment/feature/aspect, wherein the wet strength resin comprises     poly(amideamine)epichlorohydrin (PAE). -   23. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid     comprises an alpha-hydroxy acid. -   24. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid     comprises glycolic acid. -   25. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation further comprises     at least one non-ionic surfactant, at least one washing surfactant,     at least one wetting agent, at least one cationic surfactant, and     water. -   26. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid     comprises glycolic acid and the formulation further comprises at     least one propylene oxide ethylene oxide block copolymer surfactant,     at least one secondary alcohol ethoxylate non-ionic surfactant, at     least one alcohol ethylene oxide non-ionic surfactant, n-alkyl     dimethyl benzyl ammonium chloride, and water. -   27. The method of any preceding or following     embodiment/feature/aspect, wherein the at least one organic acid is     present in a stoichiometric amount to react with substantially all     of the wet strength resin that would otherwise react with the     paper-making felt. -   28. A system for making paper, comprising:

a paper-making felt that is susceptible to wet strength resin fouling when contacted with a wet strength resin;

at least one applicator configured to treat the paper-making felt with a formulation comprising at least one organic acid;

a source of the formulation in fluid communication with the applicator;

a paper-making former to apply a paper-making pulp with the wet strength resin, to the paper-making felt located downstream from said at least one applicator; and

a source of the paper-making pulp in fluid communication the paper-making former;

wherein the at least one applicator is configured to apply an amount of the formulation effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp.

-   29. The system of any preceding or following     embodiment/feature/aspect, wherein the formulation comprises     glycolic acid. -   30. The system of any preceding or following     embodiment/feature/aspect, wherein the wet strength resin in the     paper-making pulp comprises poly(amideamine)epichlorohydrin (PAE)     resin. -   31. The system of any preceding or following     embodiment/feature/aspect, wherein the paper-making felt comprises a     grid made of a polymer containing, as a recurring amide group, CONH. -   32. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation comprises from     about 0.2 wt. % to about 12 wt. % of at least one non-ionic     surfactant, from about .15 wt. % to about 7.5 wt. % of at least one     cationic surfactant, from about 1.5 wt. % to about 35 wt. % of at     least one organic acid, from about 0.1 wt. % to about 10 wt. % of at     least one washing surfactant, from about 0.05 wt. % to about 5.5 wt.     % of at least one wetting agent, based on the total weight of the     formulation, and water. -   33. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation further comprises     at least one surfactant, at least one amine, at least one     emulsifier, at least one wetting agent, and water. -   34. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation further comprises     at least amine, at least one washing surfactant, at least one     emulsifier, at least one wetting agent, at least one cationic     surfactant, and water. -   35. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation further comprises     at least one alcohol amine. -   36. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation further comprises     at least one monoethanolamine. -   37. The method of any preceding or following     embodiment/feature/aspect, wherein the formulation comprises from     about 0.2 wt. % to about 10 wt. % of at least one emulsifier, from     about 5 wt. % to about 25 wt. % of at least one cationic surfactant,     from about 0.1 wt % to about 8 wt % of at least one amine or alcohol     amine; from about 1.5 wt. % to about 40 wt. % of at least one     organic acid, from about 0.1 wt. % to about 10 wt. % of at least one     washing surfactant, from about 0.05 wt. % to about 6 wt. % of at     least one wetting agent, based on the total weight of the     formulation, and water.

The present invention can include any combination of these various features or embodiments above and/or below as set forth in sentences and/or paragraphs. Any combination of disclosed features herein is considered part of the present invention and no limitation is intended with respect to combinable features.

The present invention has many advantages, including those demonstrated in the following examples. The following examples are given to illustrate the nature of the present invention. It should be understood, however, that the present invention is not to be limited to the specific conditions or details set forth in these examples. In the EXAMPLES herein, Formulation 1 and Formulation 2 are exemplary of the present invention. Formulation 1 is the same Formulation set forth in TABLE 1 above. Formulation 2 is set forth below:

FORMULATION 2 (Formula percent is based on weight) Pluronic P 65 10% Glycolic Acid (70% water solution) 25% Ethoquad C/25 5% HDP 903-23-3 7% Tomadol 1-5 3% H₂O 50% Pluronic P 65 is a surfactant from BASF. HDP 903-23-3 is a high efficient washing agent from Harcros. Ethoquad C25 is a cationic surfactant from Eka.

EXAMPLES Example 1

The following general procedure is applicable to the experiments described in Examples 2-4. 100 grams BUBOND® 167, available from Buckman Laboratories, Inc. of Memphis, Tenn., was added to a beaker. 10% w/w NaOH solution was used to neutralize BUBOND® 167 from pH 2.8 to 7.0. 10 grams of the neutralized BUBOND® 167 solution was added to each of a series of aluminum foil trays. 2.0 grams of BUSPERSE® samples (BUSPERSE®, 59LO, or 252, also available from Buckman Laboratories, Inc.), the Formulation 1 shown in TABLE 1, and Formulation 2, were added to respective aluminum foil trays. 8.0 grams of deionized (DI) water was added to each aluminum foil tray to achieve an overall weight of 20 grams per tray. The wet strength resin solid content in the above solution was 12.5 wt. % and the apparent concentration of the BUSPERSE® was 10 wt. %, although the actual solids content might have differed. Brand new felt was cut into designated circles. The felt circles were dried at 105° C. and the dry weight was recorded and marked on the felt. Felt circle samples were respectively added to the wet strength resin solutions and soaked for 5.0 minutes until they became fully saturated. After backing up with a piece of blotter paper, treated felt circle samples were moved to a 105° C. oven for 20 minutes. The felt circle samples were then removed from the oven and respectively placed into the wet strength resin solutions again for 5 more minutes. Backing up with another piece of blotter paper, treated felt circle samples were moved to a 105° C. oven for 20 minutes. Aluminum foil trays with different wet strength resin solutions were put into a 105° C. oven overnight for more than 12 hours of heat aging.

Example 2

This example is directed to a felt weight-gain test. 200 ml glass beakers were filled with 200 ml of water. 105° C. dried felt circle samples (see Example 1) were added to each of five beakers representing Runs 1-5 shown in TABLE 2 below. Magnetic stirring at room temperature was performed overnight (for more than 12 hours) at 200 rpm. Tap water was used to remove all residues on the felt circle samples surface. Each cleaned felt circle sample was installed on a modified funnel. 250 ml room temperature tap water was used to wash each felt circle sample twice for an overall use of 500 ml water. The washed samples were vacuumed. The washings were performed one by one. The washed felt circle samples were put into a 105° C. oven. The weight change was recorded. The lower the weight gain, the better, as little gain was attributable to lower deposited amounts. Results are shown in TABLE 2 with the Formulations 1 and 2 of the present invention showing the best results.

TABLE 2 Start End Weight Weight Weight Gain Weight Run Name (g) (g) (g) Change 1 Control 2.32 2.62 0.3 12.9% 2 Formulation 1, 90 wt % 2.29 2.33 0.04 1.7% H₂O + 10 wt % Form. 1 3 Formulation 2, 90 wt % 2.34 2.36 0.02 0.9% H₂O + 10 wt % Form. 2 4 BSP 59LO, 10%, As Is 2.27 2.47 0.2 8.8% 5 BSP 252, 10%, As Is 2.24 2.61 0.37 16.5%

Example 3

This example is directed to a heat aged wet strength resin dispersion test. Overnight heat aged aluminum trays were removed from a 105° C. oven (see Example 1) and 20 ml of deionized (DI) water was added to each tray. All trays were put on a plate with magnetic stirring at 100 rpm for 10 minutes at room temperature. All residue of each aluminum tray was transferred into respective 200 ml glass beakers. Water was added to each beaker to make up a contents weight of 200 grams overall per beaker. Magnetic stirring was performed for 1 hour at 300 rpm at room temperature. Good dispersant product can have fewer big chunks of wet strength resin aggregation, and smaller or no wet strength resin gel balls. Performance was evaluated by scale from 0 to 10, the higher the number, the better the performance. Results are shown in Table 3. Formulations 1 and 2 of the present invention had excellent results.

TABLE 3 Run Name Performance Note 1 Control 0 Big and hard light yellow chunks 2 Formulation 1 8 Small and soft gel balls 3 Formulation 2 8 Small and soft gel balls 4 BSP 59LO 1 Cloudy solution with big gel balls 5 BSP 252 2 Cloudy solution with big gel balls For each of Runs 2-5, the solution was diluted to form a 10 wt % solution.

Example 4

This example is directed to a felt circle sample free drainage test. Felt circle samples, after performing the weight change test described in Example 2, were placed on respective modified funnels. Accurately weighed 100.0 g deionized (DI) water was poured into each funnel. A stop watch was started when the water was poured into the funnel. The time was recorded when the water was fully drained. The performance was evaluated as: the shorter the time, the better the felt drainage. Results are shown in TABLE 4. Formulations 1 and 2 of the present invention had the best (lowest) drainage time with the exception of the brand new felt.

TABLE 4 Time Run Name (Seconds) Note Blank 63 Brand new felt, should have the best drainage 1 Control 190 Drainage decreases significantly by WSR deposit 2 Formulation 1 100 Works well to improve drainage 3 Formulation 2 102 Works well to improve drainage 4 BSP 59LO 255 Negative impact on drainage 5 BSP 252 300 Negative impact on drainage For each of Runs 2-5, the solution was diluted to form to 10 wt % solution.

Applicants specifically incorporate the entire contents of all cited references in this disclosure. Further, when an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether such ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof. 

What is claimed is:
 1. A method of making paper, comprising: treating a paper-making felt with a formulation, the paper-making felt being susceptible to wet strength resin fouling when contacted with a wet strength resin, the formulation comprising at least one organic acid; applying paper-making pulp to the paper-making felt after the treating, the paper-making pulp comprising the wet strength resin; and making a paper from the paper-making pulp applied to the paper-making felt, wherein the at least one organic acid is applied to the paper-making felt in an amount effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp.
 2. The method of claim 1, wherein the paper-making felt comprises a continuous belt.
 3. The method of claim 1, wherein the wet strength resin fouling comprises degradation, clogging, or both.
 4. The method of claim 1, wherein the wet strength resin comprises an epichlorohydrin resin.
 5. The method of claim 1, wherein the wet strength resin comprises poly(amideamine)epichlorohydrin (PAE).
 6. The method of claim 1, wherein the at least one organic acid comprises an alpha-hydroxy acid.
 7. The method of claim 1, wherein the at least one organic acid comprises glycolic acid.
 8. The method of claim 1, further comprising applying additional amounts of the formulation to the paper-making felt after making the paper.
 9. The method of claim 1, wherein the paper-making felt comprises a rotating continuous conveyor belt and the formulation is applied at least once per revolution of the rotating conveyor belt.
 10. The method of claim 1, wherein the treating comprises spraying the formulation onto the paper-making felt.
 11. The method of claim 1, wherein the treating comprises soaking the paper-making felt in a solution comprising the formulation.
 12. The method of claim 1, wherein the formulation comprises a solution of the at least one organic acid and the pH of the solution is from about 1 to about
 3. 13. The method of claim 1, wherein the formulation further comprises at least one non-ionic surfactant, at least one washing surfactant, at least one wetting agent, at least one cationic surfactant, and water.
 14. The method of claim 1, wherein the formulation further comprises at least one surfactant, at least one amine, at least one emulsifier, at least one wetting agent, and water.
 15. The method of claim 1, wherein the formulation further comprises at least amine, at least one washing surfactant, at least one emulsifier, at least one wetting agent, at least one cationic surfactant, and water.
 16. The method of claim 1, wherein the formulation further comprises at least one alcohol amine.
 17. The method of claim 1, wherein the formulation further comprises at least one monoethanolamine.
 18. The method of claim 1, wherein the at least one organic acid comprises glycolic acid and the formulation further comprises at least one propylene oxide ethylene oxide block copolymer surfactant, at least one secondary alcohol ethoxylate non-ionic surfactant, at least one alcohol ethylene oxide non-ionic surfactant, alkyl dimethyl benzyl ammonium chloride, and water.
 19. The method of claim 1, wherein the formulation comprises from about 2.0 wt. % to about 12 wt. % of at least one non-ionic surfactant, from about 1.5 wt. % to about 7.5 wt. % of at least one cationic surfactant, from about 15 wt. % to about 35 wt. % of at least one organic acid, from about 1.0 wt. % to about 10 wt. % of at least one washing surfactant, from about 0.5 wt. % to about 5.5 wt. % of at least one wetting agent, based on the total weight of the formulation, and water.
 20. The method of claim 1, wherein the formulation comprises from about 6.0 wt. % to about 8.0 wt. % of at least one propylene oxide ethylene oxide block copolymer surfactant, from about 4.0 wt. % to about 6.0 wt. % of at least one alkyl dimethyl benzyl ammonium chloride, from about 20 wt. % to about 30 wt. % of glycolic acid, from about 4.0 wt. % to about 6.0 wt. % of at least one secondary alcohol ethoxylate non-ionic surfactant, from about 2.0 wt. % to about 4.0 wt. % of at least one alcohol ethylene oxide non-ionic surfactant, based on the total weight of the formulation, and water.
 21. The method of claim 1, wherein the at least one organic acid is present in a stoichiometric amount to react with substantially all of the wet strength resin that would otherwise react with the paper-making felt.
 22. The method of claim 1, wherein the at least one organic acid comprises glycolic acid, the wet strength resin comprises poly(amideamine epichlorohydrin (PAE), and the glycolic acid is present in a stiochiometrically sufficient amount to react with substantially all of the wet strength resin that would otherwise react with the paper-making felt.
 23. The method of claim 1, wherein the paper-making felt comprises a grid made of a polymer containing, as a recurring amide group, CONH.
 24. A method to control wet strength resin fouling on a paper-making felt comprising: treating a paper-making felt with a formulation, the paper-making felt being susceptible to wet strength resin fouling when contacted with a wet strength resin, the formulation comprising at least one organic acid; and making a paper on the paper-making felt using a paper-making pulp comprising a wet strength resin; wherein the at least one organic acid is applied to the paper-making felt in an amount effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp.
 25. The method of claim 24, wherein the wet strength resin fouling comprises degradation, clogging, or both.
 26. The method of claim 24, wherein the wet strength resin comprises poly(amideamine)epichlorohydrin (PAE).
 27. The method of claim 24, wherein the at least one organic acid comprises an alpha-hydroxy acid.
 28. The method of claim 24, wherein the at least one organic acid comprises glycolic acid.
 29. The method of claim 24, wherein the formulation further comprises at least one non-ionic surfactant, at least one washing surfactant, at least one wetting agent, at least one cationic surfactant, and water.
 30. The method of claim 24, wherein the at least one organic acid comprises glycolic acid and the formulation further comprises at least one propylene oxide ethylene oxide block copolymer surfactant, at least one secondary alcohol ethoxylate non-ionic surfactant, at least one alcohol ethylene oxide non-ionic surfactant, n-alkyl dimethyl benzyl ammonium chloride, and water.
 31. The method of claim 24, wherein the at least one organic acid is present in a stoichiometric amount to react with substantially all of the wet strength resin that would otherwise react with the paper-making felt.
 32. A system for making paper, comprising: a paper-making felt that is susceptible to wet strength resin fouling when contacted with a wet strength resin; at least one applicator configured to treat the paper-making felt with a formulation comprising at least one organic acid; a source of the formulation in fluid communication with the applicator; a paper-making former to apply a paper-making pulp with the wet strength resin, to the paper-making felt located downstream from said at least one applicator; and a source of the paper-making pulp in fluid communication the paper-making former; wherein the at least one applicator is configured to apply an amount of the formulation effective to control wet strength resin fouling due to the wet strength resin in the paper-making pulp.
 33. The system of claim 32, wherein the formulation comprises glycolic acid.
 34. The system of claim 32, wherein the wet strength resin in the paper-making pulp comprises poly(amideamine)epichlorohydrin (PAE) resin.
 35. The system of claim 32, wherein the paper-making felt comprises a grid made of a polymer containing, as a recurring amide group, CONH.
 36. The method of claim 1, wherein the formulation comprises from about 0.2 wt. % to about 12 wt. % of at least one non-ionic surfactant, from about 0.15 wt. % to about 7.5 wt. % of at least one cationic surfactant, from about 1.5 wt. % to about 35 wt. % of at least one organic acid, from about 0.1 wt. % to about 10 wt. % of at least one washing surfactant, from about 0.05 wt. % to about 5.5 wt. % of at least one wetting agent, based on the total weight of the formulation, and water.
 37. The method of claim 1, wherein the formulation comprises from about 0.2 wt. % to about 10 wt. % of at least one emulsifier, from about 0.1 wt % to about 8 wt % of at least one amine or alcohol amine; from about 5 wt. % to about 25 wt. % of at least one cationic surfactant, from about 1.5 wt. % to about 40 wt. % of at least one organic acid, from about 0.1 wt. % to about 10 wt. % of at least one washing surfactant, from about 0.05 wt. % to about 6 wt. % of at least one wetting agent, based on the total weight of the formulation, and water. 